This invention relates to an inflation passive restraint system for use in a motor vehicle for restraining a seated occupant during a collision. More particularly, it relates to an improvement in the structure of the reaction canister to reduce the potential for head injuries during low speed accidents.
The reaction canister of a vehicle passive restraint system provides protection for the gas generator and the inflatable bag until the bag deploys. A reaction canister is normally formed of a trough-shaped sidewall which may be extruded and cut to the desired length. The ends of the sidewall are closed by end plates which may be flat aluminum sheets or may also be extruded when required to reduce the machining required. An example of a reaction canister in accordance with the prior art will be found in U.S. Pat. No. 4,941,678 of Lauritzen, et al.
The reaction canister of the restraint system is normally positioned behind the instrument panel of a vehicle. The edges of the reaction canister may be within one inch, and sometimes closer, to the back surface of the instrument panel. In the event of a low speed accident without bag deployment, a person's head or other body part may make impact with the instrument panel and drive it against the edge of the reaction canister. Not only can this cause injury to the vehicle occupant, but it can also cause failure to meet standards imposed by the National Highway Safety Administration.
One approach to solving this problem has been to add flanges or rounded edges to the otherwise open edges of the reaction canister. This has helped to a degree but the canister still remains very stiff. Another approach has been to add a pattern of slots in the trough-like sidewall and in the end panels. This has helped to soften the edges but has also weakened the canister with respect to lateral displacement or "bell mouthing." It also creates potential snag points for the bag. Another approach has been to cut down the sidewalls and end plates, thereby leaving the bag exposed to act as an impact cushion. This, however, leaves the bag unsupported and unprotected.
Accordingly, it is a primary object of the present invention to provide an improved reaction canister having softened edges which yield to direct impact but resist lateral displacement. Other objects, features, and advantages will become apparent from the following description and appended claims.